1. Field of the Invention
The invention relates to the field of modules for use in networks which control the operation of devices connected to the network.
2. Prior Art
Numerous networks are known for controlling devices such as appliances, machinery, lighting, etc., connected to the network. Signals between the devices are transmitted over lines such as twisted pair lines, power lines or through radio frequency (RF) or infrared (IR) links. One such system is sold by Echelon Corporation under the trademark LONWORKS.RTM.. This system is described in part in U.S. Pat. No. 4,918,690. Another system is described in U.S. Pat. No. 5,471,190. Still another communication system is known as "X10", is manufactured by X10 USA, Ltd.
For the most part, such as shown in FIG. 1 of U.S. Pat. No. 4,918,690 and FIG. 2 of U.S. Pat. 5,471,190, the position of a first switch connected to a circuit is sensed and the state of the switch is used to control an electronic switch connected in series with a load, such as a lamp. The first switch is not in the path that includes the load.
As will be seen, the present invention departs from this arrangement by sensing the position of a first switch which is in series with the load and then uses the state of this switch to control current through the load as well as current through other remotely located loads.